Hydraulic Fracturing, or Fracking, is a recovery method used in the oil and gas industry. This process uses pressurized fluid to fracture rock in horizontally drilled wells and allow a higher recovery of oil or natural gas. Despite the effectiveness of the method, fracking is a highly controversial topic due to the possible contamination of ground water from the fracking fluid. In order to make fracking a sustainable method of recovery oil and natural gas it is necessary to find ways of treating contaminated water or eventually avoiding contaminants all together.
The Fracking Process
Figure 1. Hydraulic Fracturing Process
The fracking process can not be started until drilling has been completed. Fracking is most often used in deep horizontal wells which use directional drilling to access pockets of natural gas thousands of feet below Earth's surface.[1] Then fracking fluid, which is a mix of water, sand, and chemicals, is pumped into the well. A typical well requires 190,000 to 1,300,000 liters of water.[2] The chemicals added include gelling agents and friction reducers to help the flow of the fluid. Sand particles are used to maintain fissures within the rock once fracturing has occurred.[3] This mixture is pumped into the well at pressures between 2,000 and 8,000 pounds per square inch to induce fracturing in the shale layers and allow extraction of the natural gas.[4] The natural gas is then forced out and pumped to the surface followed by two stages of wastewater.[5] The first stage is called flowback water, which consists mostly of the fracking fluid. The second stage of wastewater is called produced water, which is a byproduct of natural gas and oil wells.[6] It is especially prevalent in wells constructed using explosive fracking methods because the process disturbs large amounts of material that has remained unaffected for so many years. This water presents economical and logistical problems such as transportation, treatment, and disposal. Wastewater from a well is often heavily contaminated with Hydrogen Sulfide, which is a naturally occurring chemical that is commonly found in sulfur springs of lakes, active geothermal areas, and natural gas deposits. Hydrogen Sulfide poses a high health risk to humans and is one of the main causes of the controversy over fracking.
The Problem
Though the fracking process has allowed access to natural gas plays that would otherwise be unreachable, it is not without its downfalls. The most immediate of these problems is the treatment and disposal of produced water from the wells. Currently the most common practice is to deep well inject the wastewater. This is because an effective form of treatment for the high levels of hydrogen sulfide has not yet been found for such large quantities of water. On average a well will produce 7 barrels of wastewater per 1 barrel of oil, and 1000 gallons of wastewater per million cubic feet of natural
Figure 2. Health Effects of Hydrogen Sulfide
gas.[7] Without an efficient form of treatment this water is now useless, so the only solution is deep well injection.Produced water is typically stored on site in either large storage tanks or in a large storage pond. The wastewater is either transported to a local deep injection well, treatment facility, or, once the well is considered depleted, the produced water is re-injected into the original well.[8] If the water contains a manageable amount of dissolved material (hydrocarbons, gases, etc.), the water is transported to a residential water treatment plant and is treated along with the other wastewaters. Typically, if the produced water contains gaseous hydrogen sulfide and the concentrations are low enough, it is simply flared into the atmosphere using a vent in the pipeline before the water is deposited into a storage area.[9] However, danger arises when hydrogen is at high concentrations and in aqueous solution within the produced water. In such cases, no longer can the gas be flared because either the exposed gas may create a health risk, or the dissolved gas will stay in solution. For this reason, many oil and gas exploration companies look specifically for hydrogen sulfide concentrations before drilling and avoid areas that contain high amounts. Usually the disposal is deep enough it does not effect the clean ground water supply, but throwing away millions of gallons of water when the country is in need of water is neither ecologically friendly nor responsible. Another problem arises with the water that remains in the original well. Since the shale has been disturbed by the fracking process this contaminated water is more likely to seep into groundwater supplies. This has the potential to harm humans and livestock because even small amounts of hydrogen sulfide can be deadly if consumed over a long period of time. Figure 2 shows the effects of different concentrations in parts per million. Until an effective and efficient treatment method is developed, hydraulic fracturing can not be considered a sustainable process.
The Solution
The growing popularity of fracking has been met head on with a growing environmental awareness in the country and as a result efforts are now being made to find a solution to this problem. Companies have formed with the sole purpose of treating wastewater from drilling, as well as universities putting together teams to research and develop treatment methods. Texas A&M University's GPRI (Global Petroleum Research Institute)[10] has put together a team to work with EFD Systems (Environmentally Friendly Drilling)[11] to research both water treatment and drilling methods that could help make fracking a sustainable process. LeTourneau University has a senior research team working on the treatment of drilling wastewater and working towards developing an effective on site method to remove hydrogen sulfide.
Due to the fact that sustainability in fracking is a relatively new topic, most teams doing research are not publicly disclosing details of their progress. Even so, it is evident that there is a rising effort to make fracking a sustainable process. Fossil fuels are essential in everyday life, and there is an abundance of natural gas in the United States that can currently only be recovered by hydraulic fracturing methods. The necessity of this process is well known, but with rising environmental concerns it is clear that something must be done to make fracking more eco friendly. As of right now hydraulic fracturing processes are in no way sustainable, but with the research efforts being made that is likely to change in the near future.
^ Fitzgerald, Timothy. (2013). Frackonomics: Some Economics of Hydraulic Fracturing. Case Western Reserve Law Review. Summer 2013. Volume 63. Issue 4.
^ Guerra, Katie, Katharine Dahm, and Steven Dundorf. (2011) "Waste Management of Cuttings, Drilling.Fluids, Hydrofrack Water and Produced Water." New York State Water Resources Institute Gas Well Drilling. U.S. Department of the Interior,<http://wri.eas.cornell.edu/gas_wells_waste.html>
Introduction
Table of Contents
The Fracking Process
The fracking process can not be started until drilling has been completed. Fracking is most often used in deep horizontal wells which use directional drilling to access pockets of natural gas thousands of feet below Earth's surface.[1] Then fracking fluid, which is a mix of water, sand, and chemicals, is pumped into the well. A typical well requires 190,000 to 1,300,000 liters of water.[2] The chemicals added include gelling agents and friction reducers to help the flow of the fluid. Sand particles are used to maintain fissures within the rock once fracturing has occurred.[3] This mixture is pumped into the well at pressures between 2,000 and 8,000 pounds per square inch to induce fracturing in the shale layers and allow extraction of the natural gas.[4] The natural gas is then forced out and pumped to the surface followed by two stages of wastewater.[5] The first stage is called flowback water, which consists mostly of the fracking fluid. The second stage of wastewater is called produced water, which is a byproduct of natural gas and oil wells.[6] It is especially prevalent in wells constructed using explosive fracking methods because the process disturbs large amounts of material that has remained unaffected for so many years. This water presents economical and logistical problems such as transportation, treatment, and disposal. Wastewater from a well is often heavily contaminated with Hydrogen Sulfide, which is a naturally occurring chemical that is commonly found in sulfur springs of lakes, active geothermal areas, and natural gas deposits. Hydrogen Sulfide poses a high health risk to humans and is one of the main causes of the controversy over fracking.
The Problem
Though the fracking process has allowed access to natural gas plays that would otherwise be unreachable, it is not without its downfalls. The most immediate of these problems is the treatment and disposal of produced water from the wells. Currently the most common practice is to deep well inject the wastewater. This is because an effective form of treatment for the high levels of hydrogen sulfide has not yet been found for such large quantities of water. On average a well will produce 7 barrels of wastewater per 1 barrel of oil, and 1000 gallons of wastewater per million cubic feet of naturalgas.[7] Without an efficient form of treatment this water is now useless, so the only solution is deep well injection.Produced water is typically stored on site in either large storage tanks or in a large storage pond. The wastewater is either transported to a local deep injection well, treatment facility, or, once the well is considered depleted, the produced water is re-injected into the original well.[8] If the water contains a manageable amount of dissolved material (hydrocarbons, gases, etc.), the water is transported to a residential water treatment plant and is treated along with the other wastewaters. Typically, if the produced water contains gaseous hydrogen sulfide and the concentrations are low enough, it is simply flared into the atmosphere using a vent in the pipeline before the water is deposited into a storage area.[9] However, danger arises when hydrogen is at high concentrations and in aqueous solution within the produced water. In such cases, no longer can the gas be flared because either the exposed gas may create a health risk, or the dissolved gas will stay in solution. For this reason, many oil and gas exploration companies look specifically for hydrogen sulfide concentrations before drilling and avoid areas that contain high amounts. Usually the disposal is deep enough it does not effect the clean ground water supply, but throwing away millions of gallons of water when the country is in need of water is neither ecologically friendly nor responsible. Another problem arises with the water that remains in the original well. Since the shale has been disturbed by the fracking process this contaminated water is more likely to seep into groundwater supplies. This has the potential to harm humans and livestock because even small amounts of hydrogen sulfide can be deadly if consumed over a long period of time. Figure 2 shows the effects of different concentrations in parts per million. Until an effective and efficient treatment method is developed, hydraulic fracturing can not be considered a sustainable process.
The Solution
The growing popularity of fracking has been met head on with a growing environmental awareness in the country and as a result efforts are now being made to find a solution to this problem. Companies have formed with the sole purpose of treating wastewater from drilling, as well as universities putting together teams to research and develop treatment methods. Texas A&M University's GPRI (Global Petroleum Research Institute)[10] has put together a team to work with EFD Systems (Environmentally Friendly Drilling)[11] to research both water treatment and drilling methods that could help make fracking a sustainable process. LeTourneau University has a senior research team working on the treatment of drilling wastewater and working towards developing an effective on site method to remove hydrogen sulfide.Due to the fact that sustainability in fracking is a relatively new topic, most teams doing research are not publicly disclosing details of their progress. Even so, it is evident that there is a rising effort to make fracking a sustainable process. Fossil fuels are essential in everyday life, and there is an abundance of natural gas in the United States that can currently only be recovered by hydraulic fracturing methods. The necessity of this process is well known, but with rising environmental concerns it is clear that something must be done to make fracking more eco friendly. As of right now hydraulic fracturing processes are in no way sustainable, but with the research efforts being made that is likely to change in the near future.
(2010). “Science in Action.” Building a Scientific Foundation for Sound Environmental Decisions. Office of Research and Development, U.S. Environmental Protection Agency. <http://www.epa.gov /ncct/download_files/factsheets/chemical_toxicity_databases.pdf>
Puder, Markus G., Deborah Elcock, Robert J. Redwick, Jr., and John A. Veil. (2010). “A White Paper Describing Produced Water from Production of Crude Oil, Natural Gas, and Coal Bed Methane Prepared For: U.S. Department of Energy National Energy Technology Laboratory” U.S Department of Energy, <http://netl.doe.gov/research/energy-analysis/publications/details?pub=2061f020-2f50-4c65-b464-779f0e23a628>
"Environmental Drilling Project". Global Petroleum Research Institute. <http://www.gpri.org/environ.html>